1. Technical Field
The present subject matter relates to semiconductor memories, and more particularly, to connecting lines from a cross point array to surrounding circuitry.
2. Background Art
Memory for computers or other electronic devices can include blocks of memory cells integrated into a larger integrated circuit or stand-alone integrated circuits. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), static RAM (SRAM), synchronous dynamic RAM (SDRAM), flash memory and phase change memory. Phase change memory devices utilize materials that have different electrical properties in their crystalline and amorphous phases. Each phase change memory cell may be programmed by putting the material in the memory cell into either a crystalline phase or an amorphous phase providing non-volatile memory that does not require power to retain its contents. Phase change memories are often programmed using heat generated by an electrical current to control the state of the phase change material.
Phase change memory arrays may be organized as a true cross-point array where the control lines, which may be referred to as bit lines and/or word lines, may be routed at a regular pitch across large portions, or even the entire, array. Some phase change memory arrays may be organized in a three-dimensional (3D) fashion, with multiple arrays stacked on each other. Such 3D arrays may use a single set of control lines to couple to two different layers of the memory array to minimize routing complexity.